Spacer assembly

ABSTRACT

A method of mounting a brake disc on a lathe for resurfacing the faces thereof employs a self-centering spacer used in conjunction with a pair of adapter cones to prevent bending of the arbor when the cones are tightened against the disc.

United States Patent [191 Mitchell Nov. 6, 1973 SPACER ASSEMBLY [75]Inventor: Wallace F. Mitchell, Arlington Heights, 111. [73] Assignee:Ammco Tools, Inc., North Chicago, III. "M"

[22] Filed: Nov. 9, 1971 [21] Appl. No.: 197,179

Related US. Application Data [62] Division of Ser. No. 66,530, Aug. 24,1970, Pat. No.

52 [15.0. ..29/559,29/406 51 int. Cl ..B23q 7/00 581 Field oiSearch..287/52.06,52.07;

279/] L, 1 J, 2 US, 16; 269/321 B, 189; 85/50 [56] References CitedUNITED STATES PATENTS Castiglia 279/2 UX 1,345,358 7/1920 Fuller 85/50 RUX 3,039,645 6/1962 Castiglia. 85/50 R X 2,426,219 8/1947 Jackson 287/53FOREIGN PATENTS OR APPLICATIONS 864,340 [/1953 Germany 85/50 R PrimaryExaminer-Richard J. Herbst Assistant Examiner-James R. DuzanAttorneyFidler, Patnaude & Batz 5 7 ABSTRACT A method of mounting abrake disc on a lathe for resurfacing the faces thereof employs aself-centering spacer used in conjunction with a pair of adapter conesto prevent bending of the arbor when the cones are tightened against thedisc.

2 Claims, 3 Drawing Figures SPACER ASSEMBLY This is a Division ofcopending application Ser. No. 66,530, filed Aug. 24, 1970 by Wallace F.Mitchell now U.S. Pat. No. 3663045.

The present invention generally relates to a spacer assembly formounting on a rod or shaft, and it relates more particularly to such anassembly for spacing two members mounted on a rod or shaft and whoseopposing faces are not precisely co-planar.

In order to machine planar faces on rotors such as brake discs, it isthe usual practice to mount such rotors on the arbor of a lathe betweena pair of adapters designed to mate with the hub portion of theparticular rotor. In the resurfacing of brake discs, these adapters aregenerally designed to mate with the conical surfaces of the outerbearing races which are fixedly spheres. The opposite end faces of theadapters are per- I pendicular to the axis' of the bores therethrough.

mounted within the hub of the brake disc. The adapters fit snugly on thearbor of the lathe and when tightened against the races of the wheeldisc, provide a driving connection between the arbor and the disc and,in addition, align the disc with the axis of the arbor. Unless theadapters are precisely aligned with the arbor and the outer end faces ofthe adapters are perpendicular to the axis of the arbor, when the nut onthe end of the arbor is tightened to clamp the brake disc between theadapters, two undesirable conditions occur. One, there is distortion inthe nature of bending of the arbor, and, two, there is uneven pressurebetween the adapters and the brake disc or between the adapter and thenut. The former condition results in wobble and run-out during machiningof the face of the disc, and the latter results in slippage of the discrelative to the arbor.

An object of this invention is, therefore, to provide new and improvedmeans for mounting a rotor such as a brake disc on the arbor of thelathe.

Another object of the present invention is to provide means for assuringproper alignment of the wheel disc and the arbor of the lathe.

A further object of the present invention is to provide a new andimproved self-aligning spacer assembly.

Briefly, the above and further objects may be realized in accordancewith the present invention by providing a pair of adapters for clampinga brake disc or other rotor therebetween on the arbor of a lathe. One ofthese adapters engages the brake disc along a circular line while theother has a conical surface complementary to a precisely located conicalsurface within the hub of the disc. A self-aligning spacer is positionedbetween the latter adapter and the end nut on the arbor so that as thenut is tightened up the wheel disc is rigidly clamped between theadapters inalignment with the axis of the arbor; If the end face of thelatter adapter is not precisely perpendicular to the axis of the arbor,due to the self-aligning nature of the spacer, 360 contact with theadjacent face of the adapter is nevertheless assured thereby preventingdistortion of the arbor when the nut is tightened and also insuring goodfrictional contact between the adjacent adapter and the brake disc.

In one embodiment of the invention the spacer assembly includes a pairof sleeves, one of which tightly fits onto the arbor and the other ofwhich has a internal diameter providing a clearance of about 0.050 inchor more with the arbor. The sleeves are held together by a resilientboot and have mutually abutting faces, one of which is spherical and theother of which is conical. For some applications the faces may becomplementary Further objects and advantages and a better understandingof the present invention may be had by reference to the followingdetailed description taken in connection with the accompanying drawingwherein:

FIG. 1 is a fragmentary sectional view of a brake disc mounted on thearbor of a lathe'by mounting apparatus embodying the present invention;and

FIGS. 2 and 3 are sectional views 'of a portion of the mountingapparatus of FIG. 1 but including a different spacer assembly embodyingthe present invention.

Referring now to the drawings and particularly to FIG. 1 thereof, thereis shown an arbor 10 connected to the spindle 12 of a lathe. An adapter14 in the form of a sleeve has an internal diameter closelyapproximating the diameter of the arbor 10 so as to fit snugly thereon.The outer end face 18 of the adapter 14 is planar and perpendicular tothe bore thereof so as to fit against the end face of the spindle 12.The wheel disc engaging surface 20 is annular and beveled so as toprovide substantially line contact with a generally conical surface 22of the wheel disc 24. The surface 22 may be the outer race of the innerwheel bearing which supports the disc 24 on the axle of the automobilewith which it is used. Consequently, the surface 22 is precisely locatedrelative to the braking surfaces 26 and 28 of the wheel disc. The wheeldisc 24 also has an outer wheel bearing which includes an outer bearingrace 30 having a conical surface 32. As is well known by those skilledin the art, the conical surfaces 22 and 32 have the same axis and itlies perpendicular to the planes of the brake surfaces 26 and 28.

A second wheel adapter 34, also sleevelike in construction, has a bore36 whose internal diameter approximates the diameter of the arbor 10 soas to fit snugly thereon. The adapter 34 has a conical surface 38 at oneend which is complementary to the conical surface 32 thereby providing alarge annular area of contact between the adapter 34 and the brake disc24 when the disc is compressed between the adpters l4 and 34. lt will benoted that the adapters 14 and 34 have similar brake disc engagingsurfaces at the opposite ends thereof for accommodating brake discs of adifferent size.

A spacer assembly 40 engages the end surface or face 42 of the adapter34 and a nut 44 is threaded onto the end of the arbor 10. It may be seenthat when the nut 44 is tightened onto the arbor 10 a force is exertedthrough the spacer assembly 40 to compress the brake disc 24 between theadapters 14 and 34. While the wheel disc 24 may rock to some extent onthe beveled surface 20 of the adapter 14 because of the line contactprovided, no such movement is permitted between the engaging surfaces 32and 38 on the race 30 and the adapter 34. Therefore, any misalignment ofthe surface 32 relative to the principal axis of the wheel disc 34 orany misalignment of the end surface 42 of the adapter 34 relative to theprincipal axis of the arbor 10 tends to result in an improper alignmentof the braking surfaces 26 and 28 relative to the axis of the arbor 10.More particularly, if the nut 44 were to directly engage the face 42 ofthe adapter 34 and anything less than 360 contact were to be providedbetween the nut 44 and the adapter 34 or between the adapter 34 and thebrake disc 24, as the nut 44 were tightened, the arbbr 10 would bedeflected. Even relatively small deflecl l l tions of the arbor areintolerable since they result in substantial wobble or run-out of thebrake disc near the edges. These discs may have a radius of aboutinches. Moreover, in order to effect maximum material removal from thesurfaces 26 and 28 during machining and further to insure a smoothsatisfactory braking surface it is important that no slippage beprovided between the brake disc and the arbor 10. Should th contactbetween the adapter 34 and the wheel disc be substantially less than 360or if the contact between the adapter 34 and the nut 44 be substantiallyless than 360 it has been found that slippage of the disc 24 on thearbor results.

In order to assure 360 contact between the adapter 34 and the wheel disc24 the spacer assembly 40 includes a first sleeve 46 having a bore 48approximating the size of the arbor 10 so as to fit snugly thereon and asleeve 50 having a bore 52 exceeding the diameter of the arbor 10 byabout 0.050 inch or more. The sleeve 46 has a planar end face 54 lyingprecisely perpendicular to the axis of the bore 48 therein and thesleeve 50 has an end face 56 which is planar and which is alsoperpendicular relative to the bore 52 therein. The sleeves 46 and 50have abutting faces or seats 58 and 60 respectively. The face 58 isspherical and the face 60 is conical thereby to provide substantial linecontact throughout a circle. A resilient boot or connector 62 maintainsthe sleeves 46 and 50 in assembled relationship. As shown, the boot 62has a pair of end flanges 64 and 66 disposed within annular grooves 68and 70 in the sleeves 46 and 50 respectively. During assembly, the boot62 is stretched over the sleeves and released so that it occupies theposition as illustrated in the drawing. The boot 62 not only functionsto maintain the sleeves in assembled relationship but it also preventsforeign matter from collecting in the space between the seats 58 and 60and retains a lubricant such as grease in such space. If desired, arecess may be provided beneath the inner surface of the boot for holdinga lubricant which may be inserted therein by means of a syringe andneedle.

In using the apparatus of the present invention as illustrated in FIG. 1to mount the wheel disc 24 on the arbor 10, an adapter 14 having anouter diameter equal to the inner diameter of the race 22 is selectedand placed on the arbor 10 adjacent the spindle 12. The wheel disc 24 isthen positioned on the arbor and an adapter 34 is placed over the arborand positioned with its conical surface 38 engaging the inner conicalsurface 32 of the outer bearing race of the disc 24. The spacer 40 isthen placed on the arbor and the nut 44 is tightened to clamp the wheeldisc 24 between the adapters l4 and 34 and thus onto the arbor 10. Anymisalignment of the adapter 34 is corrected by the selfaligning spacerassembly 40 so that it is impossible to distort or deflect the arbor 10by tightening the nut 44 thereon. Moreover, 360 contact between the nut44 and the spacer 40, between the spacer 40 and the adapter 34, andbetween the adapter 34 and the wheel disc 24 is ensured whereby slippageof the disc 24 during machining is prevented.

With reference to FIG. 1, it should be noted that the sleeve 50 havingthe oversize bore 52 therein must be adjacent to the adapter 34 tocorrect for any misalignment of the adapter 34 on the arbor 10.Accordingly, if the spacer assembly were inadvertently clamped on thearbor with the sleeve 46 in engagement with the adapter 34 noself-alignment would be provided and the machined surfaces 26 and 28might be unsatisfactory. In order to avoid this possibility, inaccordance with another feature of the present invention there isprovided a spacer assembly 75 as illustrated in FIG. 2.

The spacer assembly 75 includes a first sleeve 77 having a bore 78exceeding the diameter of the arbor 10 by about 0.050 inch or more and asecond sleeve 79 identical to the sleeve 77. The sleeves 77 and 79 havespherical faces or seats 80 and 82 respectively which engage conicalfaces or seats 86 and 88 on a sleeve 84. The bore 90 of the sleeve 84approximates the diameter of the arbor 10 so as to fit snugly thereon.Resilient means in the form of a rubber boot 92 maintains the sleeves77, 84 and 79 in assembled relationship. More particularly, the boot 92includes a pair of re-entrance annular flanges 94 and 96 at respectiveends thereof which are received in annular grooves in the sleeves 77 and79. The spacer 75 may thus be placed onto the arbor 10 with either endin engagement with the face 42 of the adapter 34 thereby eliminating anychance of error occasioned by improper positioning of the spacerassembly between the adapter 34 and the end nut 44.

While the present invention has been described in connection withparticular embodiments thereof, it will be understood by those skilledin the art that many changes and modifications may be made withoutdeparting from the true spirit and scope of the present invention.Therefore, it is intended by the appended claims to cover all suchchanges and modifications which come within the true spirit and scope ofthis invention.

What is claimed is:

1. A method of mounting a rotor to a shaft, comprising the steps offixedly placing on said shaft a first sleevelike member having anexternal annular surface,

placing said rotor on said shaft with an internal diameter surface ofsaid rotor engaging said annular surface along a substantially annulararea,

placing on said shaft a second sleevelike member with an externalannular surface thereon engaging another internal diameter surface onsaid rotor along a substantially annular area thereby preventing saidrotor from rocking on said shaft,

placing on said shaft a self-centering spacer having a planar endsurface lying perpendicular to the axis of said shaft, and

tightening a nut on said shaft against said planar end surface to clampsaid rotor between said sleevelike members,

whereby the clamping force on said shaft is axial and does not tend tobind said shaft.

2. A method according to claim 1 wherein said rotor is a brake disc andsaid shaft is the arbor of a lathe.

1. A method of mounting a rotor to a shaft, comprising the steps offixedly placing on said shaft a first sleevelike member having anexternal annular surface, placing said rotor on said shaft with aninternal diameter surface of said rotor engaging said annular surfacealong a substantially annular area, placing on said shaft a secondsleevelike member with an external annular surface thereon engaginganother internal diameter surface on said rotor along a substantiallyannular area thereby preventing said rotor from rocking on said shaft,placing on said shaft a self-centering spacer having a planar endsurface lying perpendicular to the axis of said shaft, and tightening anut on said shaft against said planar end surface to clamp said rotorbetween said sleevelike members, whereby the clamping force on saidshaft is axial and does not tend to bind said shaft.
 2. A methodaccording to claim 1 wherein said rotor is a brake disc and said shaftis the arbor of a lathe.